The use of constructions comprising ultra-hard and metallic components that are joined together is well known in the art. An example of such can be found in the form of cutting elements comprising an ultra-hard component that is joined to a metallic component. In such cutting element embodiment, the wear or cutting portion is formed from the ultra-hard component and the metallic portion of the cutting element is attached to the wear and/or cutting device. In such known constructions, the ultra-hard component can be formed from a polycrystalline material such as polycrystalline diamond (PCD), polycrystalline cubic boron nitride (PcBN), or the like, that has a degree of wear and/or abrasion resistance that is greater than that of the metallic component.
In particular examples, the ultra-hard component can be PCD that has been treated so that it is substantially free of a catalyst material, e.g., a Group VIII metal from the Periodic table, that was used to form/sinter the same at high pressure/high temperature conditions, and that comprises bonded-together diamond crystals. PCD that has been rendered substantially free of the catalyst material is referred to as thermally stable polycrystalline diamond (TSP) as removal of the catalyst material has been found to improve the thermal stability of the resulting diamond body by eliminating unwanted degradation and thermal expansion mismatches that with increasing temperature can adversely impact the effective service life of the diamond body.
While TSP provides desired improvements in thermal stability, a problem known to exist with TSP is that its lack of catalyst material within the body operates to preclude subsequent attachment of the TSP body to a metallic substrate by solvent catalyst infiltration. Further, such TSP bodies have a coefficient of thermal expansion that is sufficiently different from that of conventional substrate materials (such as WC—Co and the like) that are typically infiltrated or otherwise attached to a PCD body. The attachment of such substrates to the TSP body is highly desired to provide a TSP compact that can be readily adapted for use in many desirable applications. However, the difference in thermal expansion between the TSP body and the substrate, and the poor wettability of the TSP body due to the substantial absence of the catalyst material, makes it very difficult to bond the TSP body to conventionally used substrates. Thus, some TSP bodies must be attached or mounted directly to the desired end-use device without the presence of an adjoining substrate.
It is known that TSP bodies can be attached to a desired metallic substrate through the use of a suitable braze material. However, because of the poor wettability of the TSP body, the attachment that is formed between the TSP body and the substrate by conventional brazing techniques is one that is not as strong as the attachment bond formed between conventional PCD and a metallic substrate by infiltration, thus is one that can result in diminished service life due to delamination or the like between the TSP body and the substrate.
It is, therefore, desired that constructions comprising ultra-hard and metallic components be engineered in a manner having a desired degree of thermal stability along with an improved degree of attachment strength therebetween to enable the construction to withstand use in certain demanding wear and/or cutting applications, thereby extending the service life of such constructions when compared to conventional ultra-hard and metallic constructions.